Core B: Transgenic and Gene Targeting Core The Transgenic and Gene Targeting Core integrates with and enhances the capabilities of our exisitng Transgenic and Gene Targeting Facility with a proven track record of success in creating transgenic and knockout mice. This Core will assist COBRE investigators by providing cost-efffective serviecs for the generation, characterization, and maintenance of genetic mouse models. Ofthe 32 senior scientists in the Center, 9 are frequent users ofthe Core, and 2 of the 5 COBRE Beginning Investigator projects also have plans to utilize this facility. This Core will provide COBRE scientists with the service to microinject DNA into fertilized eggs and transfer embryos to recipient females to create transgenic mice. In addition, this Core will provide services to create chimeric mice, including the maintenance of several ES cell lines, electroporation and selection of ES cells, karyotype determination and blastocyst injection of selected ES cells. COBRE funds will be used to expand these services to include the manipulation and preparation of DNA for microinjection or gene targeting, and genotyping of transgenic and knockout mice. The Core also provides cryopreservation of mouse lines. The COBRE funds will subsidize services for Beginning Investigators and Center members and KUMC will continue to provide significant institutional support for this facility. The Facility is staffed by a Technical Director, Scientific Director, and two Research Associates, who will interface with two COBRE co-advisors.